| Summary: | We investigated the microalgal community in sea ice and in the water column of Kobbefjord, west Greenland, through an entire sea ice season, Temporal variation in physical (photosynthetically active radiation [PAR), temperature, brine volume) and chemical (salinity, nutrient concentration) properties confirmed that sea ice is a very dynamic habitat. Nevertheless, a viable sea ice algal comuunity was present throughout the year, with a species succession from flagellate dominance (dinoflagellates and cryptophytes) in December to February, followed by Chaetoceros simplex (a centric diatom) in March and pennate diatoms in May. Sea ice algal composition, biomass and productivity were influenced by PAR and brine volume, with colonization (enhanced by large brine volume) apparent during sea ice melt. Sea ice chlorophyll levels were generally low (< 0.5 mu g chl l(-1)), with 2 distinct blooms (maxima of 1.8 and 2.6 mu g chl](-1) in March and May, respectively). Primary production mirrored biomass dynamic, which had 2 seasonal peaks of ca. 21 and 15 mg Cm-2 d(-1). Integrated primary production over 7 mo was 0.8 g Cm-2 in sea ice and 94.4 g C m(-2) in the water column, with the vast majority of the pelagic production occurring just after sea ice melt (when primary production peaked at 4.2 g C m-2 d(-1)). There was no conclusive evidence of algal seeding. Sea ice algae contributed 30% of total (sympagic plus pelagic) primary production during the sea ice season, but less than 1 %, annually.
|
|---|